Worldwide, over 2 billion people suffer from worm infections in developing countries. These infections are especially damaging to the health of children, resulting in both short-term and lifelong disability. Older children with worm infections are more likely to be stunted, underweight, vulnerable to other illnesses and perform poorly in school compared to non-infected children. Large-scale deworming programs in school-age children are therefore recommended by the World Health Organization (WHO). WHO also recommends deworming of preschool-age children (as of 12 months of age) in these areas; however, the benefits of deworming, especially in the 12-24 month age group, have been inadequately studied. This knowledge is urgently needed as studies show that all children have a similar potential for healthy growth and development, provided that appropriate nutrition and health interventions are given in the critical window of opportunity before the age of two.